feat: Add GetAllClientIDsOfType query function

CHANGELOG.md

@@ -115,6 +115,8 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 ### Features
 
+* (core/02-client) [\#2855](https://github.com/cosmos/ibc-go/pull/2855) Add `GetAllClientIDsOfType` to 02-client keeper.
+* (core/24-host) [\#2855](https://github.com/cosmos/ibc-go/pull/2855) Add `PrefixedClientStorePath` and `PrefixedClientStoreKey` functions to 24-host
 * (core/02-client) [\#2819](https://github.com/cosmos/ibc-go/pull/2819) Add automatic in-place store migrations to remove the localhost client and migrate existing solo machine definitions.
 * (light-clients/06-solomachine) [\#2826](https://github.com/cosmos/ibc-go/pull/2826) Add `AppModuleBasic` for the 06-solomachine client and remove solo machine type registration from core IBC. Chains must register the `AppModuleBasic` of light clients. 
 * (light-clients/07-tendermint) [\#2825](https://github.com/cosmos/ibc-go/pull/2825) Add `AppModuleBasic` for the 07-tendermint client and remove tendermint type registration from core IBC. Chains must register the `AppModuleBasic` of light clients. 

modules/core/02-client/keeper/keeper.go

@@ -383,6 +383,28 @@ func (k Keeper) GetAllClients(ctx sdk.Context) (states []exported.ClientState) {
 	return states
 }
 
+// GetAllClientIDsOfType will iterate over the provided client type prefix in the client store
+// and return a list of clientIDs associated with the client type.
+func (k Keeper) GetAllClientIDsOfType(ctx sdk.Context, clientType string) (clientIDs []string) {
+	store := ctx.KVStore(k.storeKey)
+	prefix := host.PrefixedClientStoreKey(clientType)
+	iterator := sdk.KVStorePrefixIterator(store, prefix)
+
+	defer iterator.Close()
+	for ; iterator.Valid(); iterator.Next() {
+		path := string(iterator.Key())
+		if !strings.Contains(path, host.KeyClientState) {
+			// skip non client state keys
+			continue
+		}
+
+		clientID := host.MustParseClientStatePath(path)
+		clientIDs = append(clientIDs, clientID)
+	}
+
+	return clientIDs
+}
+
 // ClientStore returns isolated prefix store for each client so they can read/write in separate
 // namespace without being able to read/write other client's data
 func (k Keeper) ClientStore(ctx sdk.Context, clientID string) sdk.KVStore {

modules/core/02-client/keeper/keeper_test.go

@@ -386,3 +386,38 @@ func (suite KeeperTestSuite) TestGetAllConsensusStates() {
 	consStates := suite.chainA.App.GetIBCKeeper().ClientKeeper.GetAllConsensusStates(suite.chainA.GetContext())
 	suite.Require().Equal(expConsensusStates, consStates, "%s \n\n%s", expConsensusStates, consStates)
 }
+
+func (suite KeeperTestSuite) TestGetAllClientIDsOfType() {
+	paths := []*ibctesting.Path{
+		ibctesting.NewPath(suite.chainA, suite.chainB),
+		ibctesting.NewPath(suite.chainA, suite.chainB),
+		ibctesting.NewPath(suite.chainA, suite.chainB),
+	}
+
+	solomachines := []*ibctesting.Solomachine{
+		ibctesting.NewSolomachine(suite.T(), suite.chainA.Codec, "06-solomachine-0", "testing", 1),
+		ibctesting.NewSolomachine(suite.T(), suite.chainA.Codec, "06-solomachine-1", "testing", 4),
+	}
+
+	var (
+		tmClientIDs = make([]string, len(paths))
+		smClientIDs = make([]string, len(solomachines))
+	)
+
+	// create tendermint clients
+	for i, path := range paths {
+		suite.coordinator.SetupClients(path)
+		tmClientIDs[i] = path.EndpointA.ClientID
+	}
+
+	// create solomachine clients
+	for i, sm := range solomachines {
+		smClientIDs[i] = sm.CreateClient(suite.chainA)
+	}
+
+	clientIDs := suite.chainA.GetSimApp().IBCKeeper.ClientKeeper.GetAllClientIDsOfType(suite.chainA.GetContext(), exported.Tendermint)
+	suite.Require().Equal(tmClientIDs, clientIDs)
+
+	clientIDs = suite.chainA.GetSimApp().IBCKeeper.ClientKeeper.GetAllClientIDsOfType(suite.chainA.GetContext(), exported.Solomachine)
+	suite.Require().Equal(smClientIDs, clientIDs)
+}

modules/core/02-client/migrations/v7/store.go

@@ -151,7 +151,7 @@ func handleLocalhostMigration(ctx sdk.Context, store sdk.KVStore, cdc codec.Bina
 // for tendermint clients is included as only one tendermint clientID is required for
 // v7 migrations.
 func collectClients(ctx sdk.Context, store sdk.KVStore, clientType string) (clients []string, err error) {
-	clientPrefix := []byte(fmt.Sprintf("%s/%s", host.KeyClientStorePrefix, clientType))
+	clientPrefix := host.PrefixedClientStoreKey(clientType)
 	iterator := sdk.KVStorePrefixIterator(store, clientPrefix)
 
 	defer iterator.Close()

modules/core/24-host/keys.go

@@ -55,6 +55,18 @@ func FullClientKey(clientID string, path []byte) []byte {
 	return []byte(FullClientPath(clientID, string(path)))
 }
 
+// PrefixedClientStorePath takes a client type and returns a prefixed key path
+// which can be used to iterate over client stores belonging to a certain client type.
+func PrefixedClientStorePath(clientType string) string {
+	return fmt.Sprintf("%s/%s", KeyClientStorePrefix, clientType)
+}
+
+// PrefixedClientStoreKey takes a client type and returns a prefixed key
+// which can be used to iterate over client stores belonging to a certain client type.
+func PrefixedClientStoreKey(clientType string) []byte {
+	return []byte(PrefixedClientStorePath(clientType))
+}
+
 // ICS02
 // The following paths are the keys to the store as defined in https://github.com/cosmos/ibc/tree/master/spec/core/ics-002-client-semantics#path-space